Numpy (6)

How to replace items that satisfy a condition without affecting the original array?

arr = np.arange(10)
out = np.where(arr % 2 == 1, -1, arr)

arr
#>  array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
out
#>  array([ 0, -1,  2, -1,  4, -1,  6, -1,  8, -1])